Pump having reciprocating pipe and slidably supported hollow body

ABSTRACT

A bore hole pump which eliminates the need for a piston sealingly engaging with the walls of the pump body. The pump comprises a hollow body closed at its lower end by a non-return inlet valve and slidably and sealingly supporting at its upper end, via a seal, a reciprocating riser pipe which is likewise closed at its lower end by a non-return valve. Upward movement of the riser pipe causes fluid to be drawn into the pump body via inlet valve while downward movement of the riser pipe causes fluid to be expelled from the pump body via outlet valve.

This invention relates to pumps.

Conventional pumps generally comprise a pumping cylinder whichaccommodates a piston whereby on relative reciprocation between thecylinder and the piston, fluid is drawn into one end of the cylinderthrough an inlet and then is transferred to the other side of the pistonto pass from the other end of the cylinder.

One disadvantage of piston pumps is that it is generally more difficultto produce a smooth cylindrical interior surface than a smoothcylindrical exterior surface. This is particularly the case in the tubemanufacture. Therefore the production of a smooth bored cylinder for apiston pump usually requires special machining of that surface.

In addition during the pumping action of the piston pump with themovement of the piston towards one or the other end there is usually anincrease in sealing pressure between the piston seal and cylinder wall.This increase in pressure tends to increase the frictional contactbetween the piston seal and the cylinder and since the circumference ofthe cylinder bore is usually maximized to maximise the pumping volume ofthe pump the frictional forces so produced can be relatively large.

A further disadvantage of piston pumps particularly pumps used in boreholes arises from the fact that the fluid being pumped generally carrieswith it abrasive and/or corrosive materials which cause abrasion of thecylinder bore and the piston seal on reciprocation of the piston withinthe cylinder due to the intimate contact between the piston seal and thefluid being pumped. It is also common for solid abrasive particles tobecome lodged between the piston body and the bore adjacent the seal toprovide a source of considerable abrasive action.

As a result of the frictional contact between the seal and the cylinderbore the resultant abrasion of that seal and cylinder bore during theuse of the pump is common for there to be some leakage, althoughminimal, past the piston during usage and after usage of the pump. Inmost cases the leakage past the piston during usage can be toleratedhowever if such leakage occurs when the pump is not in use the fluidwhich lies above the piston will drain away from the riser pipe andcylinder. When the pump is used again it is necessary to prime the pumpand/or there is some delay betwen the initiating of the pumping actionto the delivery of the first fluid from the outlet of the pump. Thenecessity to prime the pump before usage is of considerable disadvantagedue to the need to maintain a supply of fluid to effect priming of thepump. The delay in delivery of the fluid is also of a disadvantage wherethe pump being used by a drive source which is variable in its operationsuch as a solar powered drive or a wind powered drive where the energysource which effects the drive will vary in its incidence.

It is an object of this invention to provide a pump which eliminates theneed for a piston sealingly engaged with the walls of a cylinder.

In one form the invention resides in a pump having a hollow body havingan inlet controlled by a first nonreturn valve which permits the entryof fluid into the body, said pump being characterised by a pipe, one endof which extends into the hollow body, said pipe being slidably recievedwithin said body, a seal being located between the hollow body and thepipe, a second non-return valve within said pipe to permit the entry offluid from within the body to the pipe past the second non-return valve,and a drive means to cause relative reciprocation between the pipe andthe body.

The invention will be more fully understood in the light of thefollowing description of several specific embodiments. The descriptionis made with reference to the accompanying drawings of which:

FIG. 1 comprises a schematic sectional elevation of a pump according tothe first embodiment during the upstroke portion of the pump cycle;

FIG. 2 comprises a schematic sectional elevation of the pump accordingto the embodiment during the downstroke of the pump cycle;

FIG. 3 is a schematic sectional elevation of a pump according to thesecond embodiment during the upstroke portion of the pump cycle;

FIG. 4 is a schematic sectional elevation of a pump according to thesecond embodiment during the downstroke of the pump cycle;

FIG. 5 is schematic sectional elevation of a third embodiment of theinvention;

FIG. 6 is a schematic sectional elevation of the fourth embodiment ofthe invention;

FIG. 7 is a schematic sectional elevation of a fifth embodiment;

FIG. 8 is a schematic sectional elevation of a sixth embodiment;

FIG. 9 is a schematic sectional elevation of a seventh embodiment; and

FIG. 10 is a sectional view along line A--A of FIG. 9.

The first embodiment shown at FIGS. 1 and 2 relates to a bore hole liftpump which comprises a pump body 11 which is to be located at the lowerend of a bore hole and has located at its lower end, an inlet closed bya one way foot valve 13. The inlet is associated with a screen orstrainer 12 which serves to eliminate most of the solid particlescarried in the water to be pumped. The lower end of the screen 12 isconnected to a weighted anchor 18 which serves to assist in retainingthe pump body 11 within the bore hole. The upper end of the pump body 11slidably supports a riser pipe 14 which is supported in the bore holefrom the top thereof to reciprocate within the bore hole and within thepump body 11. An annular seal 16 is mounted at the upper end of the pumpbody 11 to sealingly and slidably engage with the external walls on theriser pipe 14. Preferably the seal 16 takes the form of a lip sealwhereby the lip is directed inwardly in relation to the pump body 11. Ifdesired to protect the seal from any abrasive material a cover may beprovided over the seal at the upper end of the pump body to be slidablyreceived over the riser pipe 14. The lower end of the riser pipe 15supports a second non-return valve 15 which permits the entry of waterfrom within the pump body to within the riser pipe 14.

In operation when the riser pipe 14 is caused to move upwardly withinthe pump body 11 water is caused to be drawn into the pump body 11through the one way foot valve 13. On movement of the riser pipe 14downwardly within the pump body 11 and the one way foot valve 13 isclosed while the one way lift valve 15 at the lower end of the riserpipe is caused to open to cause the flow of fluid into the riser pipe14. With continued reciprocation of the riser pipe fluid is transferredinto the pipe body 11 and then to the riser pipe 14 where it is causedto flow upwardly. To assist the drive in effecting movement of the riserpipe in its downstroke and in order to at least partially overcome thefluid friction induced during the flow of the fluid through the riserpipe 14, a weight 17 or suitable biassing means is provided on the riserpipe above the pump body 11. The weight may not be required if theweight of the pipe is sufficient and if the pipe is well guided.

As a result of the embodiment a bore hole lift pump is produced wherebyfriction is induced in the fluid flow only during the downstroke of theriser pipe during which time water is caused to enter the riser pipe.During this downstroke such frictional forces are at least partiallyovercome by the dead weight of the riser pipe 14 and the weight 17.During the upstroke of the riser pipe the main force to be overcome bythe driving means effecting reciprocation in the riser pipe is thatproduced by the dead weight of the riser pipe and the weight of thewater within the riser pipe. This weight of water is the same as thatwhich would be induced in a conventional form of lift pump.

The avoidance of the need to provide a piston sealingly engaged with thewalls of the pump body avoids each of the disadvantages referred toabove the ensures that the only point of leakage of water from the riserpipe 14 is through the one way lift valve 15 which is less likely tosuffer abrasion or malfunction as a result of use than the conventionalpiston seal.

The provision of the seal 15 between the pump body 11 and the riser pipe14 at the upper end of the pump body 11 ensures that the seal is notbeing immersed in the fluid being pumped and the effect of any abrasiveparticles contained by the fluid being pumped and/or the corrosivenature of the fluid being pumped is minimised. Furthermore if such aseal could suffer any damage any fluid leakage from the pump body isunlikely to produce any delay between commencement of the pumping actionand delivery of the pumping fluid or the need to prime the pump due tothe presence of the non-return valve 15 at the lower end of the riserpipe 14. In addition if a lip seal is used as a seal 16 between the pumpbody 11 and the riser pipe 14 such that the lip seal is directedinwardly in relation to the pump body any abrasive particles that maygather in the region of the seal will be drawn into the pump body duringthe upstroke of the riser pipe due to the flow of liquid produced intothe pump body 11 past the seal 16. During the downstroke of the riserpipe 14 the increase in pressure within the pump body will cause the lipseal to bear against the riser pipe 14 however the frictional forces socreated are somewhat alleviated by the effect of the movement of theriser pipe in the direction of bias of the lip seal. Furthermore sincethe circumference of the riser pipe 14 is considerably less than that ofthe pump body 11 the area available for creation of the frictional forceby the seal 16 is minimised in comparsion to that which would be createdby a piston seal within the pump body 11. Furthermore as statedpreviously the production of the smooth exterior surface on a tube ismore readily created than the smooth interior surface of a tubeparticularly where the tubes are formed by extrusion techniques andtherefore it is not necessary for the exterior surface of the riser pipe14 to be machined to provide for an adequate seal with the seal 16.

A further advantage offered by the embodiment resides in the reducednumber of components which need to be provided due to the absence of apull rod, guide or piston.

It may be preferable to provide guides around the riser pipe 14 atspaced locations along its length to ensure that the riser pipe remainssubstantially central within the bore hole during use and it may also bedesirable to locate a guide a the lower end of the riser pipe 14 withinthe pump body 11 to ensure that the riser pipe remains substantiallycentral within the pump body 11.

The second embodiment as shown at FIGS. 3 and 4 is similar to the firstembodiment and in the light of such the same reference numerals havebeen used in respect to corresponding components. The second embodimentdiffers from the first embodiment in that the one way lift valve 15 inthe riser pipe 14 is located at a point spaced from the end of the riserpipe. The provision of the one way lift valve 15 in a portion of theriser pipe 14 which is clear of the pump body 11 enables the valve to beof a larger construction than the valve of the first embodiment. Thisfeature serves to reduce the fluid friction caused by movement of fluidthrough the valve.

If desired the pump body 11 of the first and second embodiments may beassociated with a clamping means capable of releasably retaining thebody within the bore hole. Such means may be pneumatically orhydraulically or mechanically operated. In addition the pump of thefirst and second embodiments may be used in lined or unlined bore holes.

The third embodiment of FIG. 5 utilises a bore hole casing 120 as thepump body of the first and second embodiments whereby the casing 120 islocated in the bore hole and a suitable screen 112 is located at thelower end of the casing. The lower end of the casing 120 supports a oneway foot valve 113 which may be mounted to the lower end of the casingprior to the casing being located in the bore hole or alternatively maybe lowered and fixed into the casing 120 subsequent to the bore holecasing being located in the bore hole. The casing 120 further supports acollar 121 at a point spaced above the one way foot valve 113 which maybe located within the casing 120 before or after the casing is locatedin the bore hole. The collar 121 supports an inverted lip seal 116whereby the lip of the seal is directed inwardly towards the one wayfoot valve 113. The collar 121 is formed with an upper edge which isinclined inwardly to provide a converging guide into the central portionof the collar 121. The pump of the third embodiment further comprises ariser pipe 114 which is slidably and sealably engaged by the lip seal116 within the collar 121 and which supports a one way lift valve 115 ata point in the riser pipe which is spaced above the collar 121. Theupper end of the riser pipe 114 is connected to a driving means whichcauses reciprocation of the riser pipe 114 within the casing 120. Theresult of the reciprocation of the lower end of the riser pipe 114within the casing 120 between the foot valve 113 and the lip seal 116causes the pumping of liquid upwardly through the riser pipe 114 pastthe fixed valve 115 in the manner described above in relation to thefirst and second embodiments. The lower end of the riser pipe 114 can beused to engaged the foot valve 113 when at its lowermost position in thebarrel 111 to facilitate removal of the foot valve 113 and thus the seal116 on extraction of the riser pipe 114.

The advantage offered by the third embodiment relates to the simplicityof its construction and installation and the resultant simplification ofany maintainence procedures.

The fourth embodiment of FIG. 6 is similar in principle to the previousembodiment and comprises a pump body 211 which is capable of limitedaxial movement within the bore hole. The lower end of the body isassociated with a foot valve 213 which is formed by a valve seat 213adefined by an inwardly directed annular flange at the lower end of thebody. The valve seat 213a is engageable with a fixed valve member 213bwhich extends upwardly from the base of the bore hole and is supportedtherein by an anchor 218. The lower end of the pump body 211 isassociated with a strainer 212 which extends around the foot valve 213and is slidable over the support for the valve member 213b. The upperend of the pump body 211 supports a seal 216 defined by an annular lipseal whereby the lip is directed inwardly in relation to the pump body211. The seal 216 slidably and sealing receives the riser pipe 214 whichis supported at its upper end by a driving means which effectsreciprocation of the riser pipe 214 within the bore hore above the lowerend of the riser pipe 214 within the pump body 211. As in the thirdembodiment of FIG. 5 the riser pipe supports a one way lift valve 215 ata point in the length of the riser pipe 214 above the seal 216. The areaof the annular space between the riser pipe 214 and the internal bore ofthe pump body 211 is less than the area of the annular flange whichdefines the valve seat 213a of the foot valve 213.

In use as the riser pipe 214 is caused to move upwardly within the borehole the reduction in pressure created within the pump body 211 as aresult of such movement causes the pump body 211 to move upwardly withinthe bore hole such that the valve seat 213a moves clear of the valvemember 213b allowing the flow of water into the pump body 211. Oncompletion of the upward stroke of the riser pipe 214 and thecommencement of the downstroke 214 the resultant increase in pressurewithin the pump body 211 increases the force upon the annular flangedefining the valve seat 213a of the foot valve 213 which is greater thanthe upwardly directed force upon the seal 216. The resultant effect isthat the pump body is caused to move downwardly to bring the valve seat213a into sealing engagement with the valve member 213b and as a resultwater within the pump body 211 is caused to flow into the riser pipe 214past the one way lift valve 215.

As a result of the embodiment a bore hole pump is produced whereby theriser pipe and pump body 211 may be extracted from the bore hole forservicing to leave the anchor 218 and valve member 213b within the borehole. If desired the anchor 218 may be rendered removable from the boreto facilitate servicing of the valve member 213b. In addition ifappropriate suitable guides may be provided between the exterior of theriser pipe 214 and the interior of the pump body 211 and between theexterior of the riser pipe 214 and the bore hole.

The fifth embodiment shown at FIG. 7 is similar to the fourth embodimentof FIG. 6 and similar reference numerals have been used in respect ofcorresponding components. The significant difference of the fifthembodiment from the fourth embodiment relates to the provision of acollar 217 which accommodates the one way lift valve. The collar servesin engaging the top of the barrel at the lowermost position of the riserpipe 214 in the barrel 211. This feature enables the valve seat 213a tobe driven down onto the valve member 213b to break up and clear anymaterials captured thereby which may prevent the closing of the valve.

In addition the lower end of the riser pipe 214 supports a lower collarmember 222 which engages the seal housing 223 at the top of the barrel211 at the uppermost position of the riser pipe 214 in the barrel 211.This feature facilitates extraction of the barrel 211 from the bore holewhen the riser pipe is extracted. The supporting shank 225 for the valvemember 213b is frictionally retained in the anchor 218 and has a rib 224which can be engaged by the strainer 212 when the barrel 211 is liftedfrom the bore hole to enable the valve member 213b to be extracted.

If desired the valve member 213b may be fixed to the anchor 218 and thestrainer 212 is retained on the valve member 213a by a resilient rib orlike means which the strainer can be pulled over when the barrel 211 isextracted from the bore hole.

The sixth embodiment shown at FIG. 8 is similar in form to the fourthand fifth embodiments of FIGS. 6 and 7 and similar reference numeralshave been used in respect of corresponding components other than theconfiguration of the one way foot valve 213. The sixth embodimentincludes a variation in the form of the one way lift valve 215. The liftvalve 215 comprises a fixed valve member 215b which is suspended fromthe end of the riser pipe and is engaged by a valve seat 215a which issupported from the lower end of the riser pipe 214 by a flexiblecoupling 226. As the riser pipe is lifted the flexible coupling 226extends to allow the valve seat 215a to engage with the valve member215b. As the riser pipe descends the flexible coupling 226 will contractto allow the valve seat 215a to lift from the valve member 215b.

The seventh embodiment shown at FIG. 9 is similar to the first andsecond embodiments of FIGS. 1-4 and similar reference numerals have beenused for corresponding components.

The seventh embodiment differs from the first and second embodiment inthe form of anchor 18 which comprises a clamping collar mounted to theupper end of the barrel and which is engagable with a correspondingabutment 27 on the bore casing. In addition the anchor 18 houses theseal 16 which takes the form of a multiple lip seal.

As in the fifth embodiment the seventh embodiment has a first collarwhich accommodates the one way lift valve on the riser pipe 14 whichengages the upper end of the barrel 11 at the lowermost position of theriser pipe 14 in the barrel 11. The lower end of the riser pipe 11 alsosupports a second collar 22 which will engage with the lower end of thebarrel 11 at the lowermost position of the riser pipe 14 in the barrel11. The second collar 22 facilitates extraction of the barrel 11 fromthe bore hole when the riser pipe 14 is extracted. Beyond the secondcollar 22 the riser pipe is formed with an extension piece 28 which willextend into the one way foot valve 13 to drive the valve member 13bagainst the valve seat 13a when the riser pipe is at its lower positionin the barrel. This enables any foreign matter between the valve memberand valve seat to be broken up and cleared from the foot valve 13 ifpresent.

The valve member 13b is retained in the region of the valve seat byinwardly extending lugs 29 located around the interior of the valve body30 above the valve seat 13a.

It should be appreciated that in the fifth and seventh embodiments thelowermost position of the riser pipe in the barrel referred to is notusually attained during normal pumping operations but is only attainedwhen it is necessary to clear the foot valve of foreign matters.

In summary, the advantages offered by the pumps of each of theembodiments described above over those pumps which utilise areciprocating piston within the cylinder bore may be summarised asfollows:

1. A seal between the pump body and the reciprocating riser pipe isuppermost in the pump body and is not positioned in the main fluid flow.Therefore the possibility of sand and grit being captured by the sealand substantially reduced. Furthermore any grit which finds its way intothe seal should tend to move out from the seal due to fluid flow pastthe seal.

2. The number of components is minimised since there is no pull rod orpull rod guides.

3. Flow friction is minimised for a given riser pipe diameter due to theabsence of a pull rod within the riser pipe.

4. The sliding seal surface is external to the plunger rod whichfacilitates the provision of a smooth surface.

5. The previous feature provides the possibility of a longer pumpingstroke which offers increased pump efficiency.

6. The pump body and riser pipe are readily extracted from the bore holefor maintanence and inspection.

7. The work done per cycle is split into two components:

(i) bore water lifting is performed on the upward stroke;

(ii) flow friction, plus flow work above ground, are together overcomeon the downstroke. This facilitates a more convenient match to theoutput of a simplex vapour expander or its equivalent. The pistonexpander usually delivers greater force at the begining of its strokethen towards the end. This is not well matched to a steady resistanceprovided by the usual water pumping action. With the pump of each of theembodiments the expander is overcoming only dead weight and inertia. Itcan therefore be designed to efficiently apply the greater force toovercome inertia and produce upward acceleration of the water column anddead weight. Thus good coupling may be achieved.

8. The design is appropriate for the use of plastics materials (e.g.PVC) with the resultant reduction in cost and corrosion.

9. The pump is able to be used in bore holes having a smaller diameterthan is currently the situation.

10. Due to the absence of a seal between relative reciprocating surfaceswhich is also required to retain fluid in the riser pipe the possibilityof leakage from the riser pipe back into the pump body is significantlyreduced thus eliminating the need for priming and/or any excessive delaybetween the recommencement of the pumping action and the delivery offluid.

11. The pump is robust since the only points of failure other than theone way valves and the seals relates to the interconnection of thevalves to the barrel and riser pipe and the lengths of pipe which makeup the riser pipe.

12. It is possible to operate on the foot valve when installed to clearthat valve of debris or the like.

In order to drive the pumps of any of the embodiments described aboveany reciprocatory drive may be used. It is envisaged that the pumpsdescribed in each of the embodiments may be particularly applicable tohand pumping situations.

It should be appreciated that the scope of the present invention neednot be limited to the particular scope of the embodiments describedabove. In particular the invention need not be restricted to bore holepumps only. It may be used in any other pumping situation.

The claims defining the invention are as follows:
 1. A pump of the typeadapted to be lowered into a body of fluid for pumping fluid therefromcomprising a pipe having an open lower end and an upper discharge endfor discharging pumped fluid from a point above the body of fluid, saidpipe being reciprocal through a normal pumping stroke, first check valvemeans for permitting flow into said pipe through said open lower end, ahollow body slidably supported upon the lower end of said pipe anddefining a cavity into which said open lower pipe end extends, sealmeans interposed between an upper end of said hollow body and said pipefor sealing the upper end of said cavity, said hollow body having notportion that is engaged by said pipe upon normal pumping reciprocatingof said pipe so that said hollow body is not physically reciprocated bycontact with said pipe upon normal pumping reciprocation of said pipe,an opening formed at the lower end of said hollow body, and a secondcheck valve for controlling the flow through said hollow body openingfor permitting flow into said hollow body cavity and for precluding flowout of said opening, said second check valve comprising a first elementfixed relative to said hollow body and a cooperating second elementadapted to be fixed relative to the body of fluid, and said pipe beingreciprocated between a raised position and a lowered position during thenormal pumping reciprocation thereof, the reciprocation of said pipeinto said raised position effecting a pressure difference upon saidhollow body by the fluid in the fluid body for moving the first elementof said second check valve away from the second element of said secondcheck valve for permitting flow of fluid into said hollow body cavitysolely due to fluid pressure variations, movement of said pipe in adownward direction being effective to permit said hollow body to movefor bringing said first element into sealing engagement with secondelement for pressurizing the fluid in said hollow body cavity fordriving said fluid upwardly through said first check valve into saidpipe and be discharged through said upper discharge end.
 2. A pump asclaimed at claim 1 wherein the innermost configuration of the hollowbody is such that on the fluid pressure within the hollow bodyincreasing the resultant force created thereby causes the fixed elementof the hollow body to move into engagement with the cooperating secondelement.
 3. A pump as claimed at claim 1 wherein the pump comprises awater lift pump.
 4. A pump as claimed at claim 1 wherein said firstcheck valve comprises a valve member fixed to said pipe and a valve seatfixed from said pipe with an extensible coupling in the pipe between thefixing for the valve seat and the valve member whereby said valve memberwill seal with the valve seat on a positive pressure differentialexisting in the interior of the pipe remote from the hollow body throughextension of the coupling.
 5. A pump as claimed at claim 1 furtherincluding a strainer affixed to the lower end of the hollow body andencircling the second check valve, said strainer being associated withsaid second valve element for lifting said second valve element uponlifting of the pipe above the raised position.
 6. A pump as claimed atclaim 1 wherein the hollow body is tubular.
 7. A pump as claimed atclaim 6 wherein the hollow body supports the second check valve at oneend of said hollow body and the seal at the other end of said hollowbody.
 8. A pump as claimed at claim 1 wherein the seal comprises a lipseal, the lip of which is directed inwardly in relation to the hollowbody.
 9. A pump as claimed at claim 8 wherein the seal comprises amultiple lip seal.
 10. A pump as claimed at claim 1 wherein meanscarried by the pipe engages the hollow body when the pipe is movedbeyond the lowered position to drive the first valve element intoengagement with the second valve element.
 11. A pump as claimed at claim10 wherein the means carried by the pipe which engages the hollow bodybeyond the lowest position of the pipe comprises a valve housingcontaining the first check valve element.
 12. A pump as claimed at claim1 wherein the portion of the pipe accommodated within the hollow body isformed with a collar which is engagable with the hollow body on the pipebeing raised above the raised position for raising the hollow body. 13.A pump as claimed as claim 12 further including a strainer affixed tothe lower end of the hollow body and encircling the second check valve,said strainer being associated with said second valve element forlifting said second valve element upon lifting of the pipe above theraised position.